How a Pituitary Tumor May Cause a Severe Headache

Most headaches, while painful and disruptive to our lives, are not indicative of a more serious medical condition. In unusual circumstances, though, your headache may be the first sign that something dangerous is going on in the body. Pituitary tumor apoplexy is one example of a rare but potentially life-threatening condition that causes a severe, sudden headache.

Pituitary gland illustration
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Pituitary Basics

The "pituitary" part of this condition refers to the pituitary gland, an organ that sits at the base of the brain. This gland is often referred to as the master gland because it releases a number of hormones into the body.

Summarized below is a list of hormones made by the pituitary gland:

  • Thyroid-stimulating hormone (TSH): Stimulates the thyroid gland—located in the neck—to release thyroid hormones, which control how the body makes and uses energy.
  • Adrenocorticotropic hormone (ACTH): Stimulates the adrenal glands—allocated on top of the kidneys—to release the hormone cortisol, which controls how the body manages sugar levels and stress.
  • Luteinizing hormone/follicle-stimulating hormone (LH/FSH): Stimulates the ovaries in a female to release estrogen and progesterone and the testicles in a male to release testosterone.
  • Prolactin: Stimulates milk production in lactating women.
  • Growth hormone: Regulates growth and muscle/fat balance.

Pituitary Tumor Apoplexy

In pituitary apoplexy, there is either bleeding into the pituitary gland or a loss of blood supply to the gland. In most, but not all cases of pituitary apoplexy, the patient already has a pituitary tumor. The tumor grows over the gland and often prevents the release of certain hormones, especially if the tumor is large. But sometimes a person does not know they have a tumor until apoplexy or bleeding into the gland occurs.


A person with pituitary tumor apoplexy usually has a sudden-onset, severe headache at the front of the head (either located on one side of the head or both) and/or behind one or both eyes. A person may also have hormone deficiencies from the bleeding tumor, which affects the pituitary gland's ability to release hormones. For example, a person with pituitary apoplexy may have low blood pressure and low blood sugar from ACTH deficiency.

Other symptoms of pituitary tumor apoplexy may include:

  • Nausea/vomiting
  • Vision changes
  • Fever
  • Stiff neck
  • Confusion


According to a 2001 study at Emory University School of Medicine in the Journal of Neurology, Neurosurgery, and Psychiatry, factors that increase a person's chance of developing pituitary apoplexy include:

  • Trauma
  • Pregnancy
  • Severe illness like a heart attack
  • Severe infection

Besides the above, research also suggests having high blood pressure (hypertension), taking an anticoagulant (blood thinner), or undergoing radiation therapy may predispose a person to pituitary apoplexy.

Diagnosis and Treatment

Pituitary tumor apoplexy is a medical emergency and requires immediate imaging with either a ​CT scan or ​MRI of the brain. It can resemble other medical conditions listed below, so it's important to obtain a thorough evaluation by an emergency room doctor.

Examples of other serious medical conditions that may cause a severe, sudden headache similar to pituitary tumor apoplexy include:

  • Subarachnoid hemorrhage
  • Cerebral venous thrombosis
  • Meningitis/encephalitis
  • Hypertensive emergency
  • Cervical artery dissection

Once a person is diagnosed with pituitary tumor apoplexy, she will usually be given fluids and steroids through the vein, especially if ACTH deficiency is suspected. Then a person will be monitored closely in the hospital for any vision, neurological, or hormone changes. Sometimes brain surgery is needed to stabilize the bleeding and/or remove the tumor.

Long-term follow-up is important for people with pituitary tumor apoplexy. A person will commonly need to see a neurosurgeon and endocrinologist for repeat MRI imaging of the pituitary gland and regular hormone blood tests.

A Word From Verywell

While this condition is rare and the vast majority of headaches do not have a worrisome cause, it's important that you are aware of your headache patterns, triggers, and course. If your headache has warning signs, it's critical to seek medical attention right away.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Hannoush ZC, Weiss RE. Pituitary Apoplexy. In: Feingold KR, Anawalt B, Boyce A, et al., editors. Endotext [Internet]. South Dartmouth (MA):, Inc.

  2. Ranabir S, Baruah MP. Pituitary apoplexyIndian J Endocrinol Metab. 2011;15 Suppl 3:188-96. doi:10.4103/2230-8210.84862

  3. Biousse V, Newman NJ, Oyesiku NM. Precipitating factors in pituitary apoplexy. J Neurol Neurosurg Psychiatry. 2001;71(4):542-5. doi:10.1136/jnnp.71.4.542

By Colleen Doherty, MD
 Colleen Doherty, MD, is a board-certified internist living with multiple sclerosis.